1. Technical Field of the Invention
The present invention relates to an apparatus and a method for dissolution reaction that can, for instance, prevent growing of scale in devices and effectively use slurried fly ash as a cement material.
2. Description of the Related Art
Fly ash generated at incineration facilities and the like is added to cement kilns as slurry after desalinated through washing since chlorine included in the fly ash is an obstacle when used as a cement material.
However since the slurry in which the fly ash dissolves includes calcium-containing compounds such as calcium hydroxide, scale grows in pipes for transporting the slurry and the like, which necessitates regular removal of the scale sticking to the pipes and the like, and becomes a great factor to lower the operation rate of devices for materializing the fly ash.
To solve the above problem, for instance, in the first patent document, a technology is described. In this technology, when exhaust gas including carbon dioxide for neutralization is blown through a blowing nozzle to a fly ash detoxification tank which accommodates water in which the fly ash dissolves, in order to prevent clogging of the exhaust-gas-blowing nozzle, which is caused by sticking of scale of calcium carbonate thereto, the calcium carbonate generated by neutralization is concentrated, and is circulated again as seed crystals from a seed crystal returning pipe to the fly ash detoxification tank.
Further, in the second patent document, a method effective to prevent growing of scale is described. In this method, carbon dioxide is blown to slurry in which fly ash dissolves, which causes calcium-containing compounds dissolved in the slurry to be separated out. In addition, a diffusion plate for blowing the carbon dioxide is disclosed. The diffusion plate is made of rubber with elasticity, and the plate keeps plane shape before gas is blown, and expands outward after the blowing.
Patent document 1: Japanese Patent Publication Heisei 8-108038 gazette
Patent document 2: International Patent Publication WO 2004/030839 gazette